Get the scoop on dietary guidelines for key nutrients, such as carbs, protein, fat, sugar and salt.
By Mayo Clinic Staff

You're trying to eat a healthy diet, but you're not sure how much of which nutrients to get. Just what constitutes a healthy diet? With the different or even conflicting nutritional advice in the media, it's no wonder you're uncertain.

Here's the bottom line on what you should eat to help promote health and prevent disease, based on the Dietary Guidelines for Americans from the Department of Agriculture.

Use this guide to help plan your healthy diet. If you have high blood pressure, heart disease or other conditions, ask your doctor or dietitian if you need to adjust any of these recommendations.

Carbohydrates are your body's main energy source. And your brain is fueled by carbohydrates. Carbohydrates occur in a variety of forms: simple sugars, more complex starches and fiber. They are found naturally in legumes, grains, vegetables, fruits and milk. They're also added to baked goods and many other foods.

Recommendation: Emphasize natural, nutrient-dense carbohydrates from fruits and vegetables, beans and legumes, and whole grains. Limit less healthy sugar-sweetened beverages, desserts and refined grain products. Get 45 to 65 percent of your daily calories from carbohydrates. Carbohydrates have 4 calories a gram. Based on a 2,000-calorie-a-day diet, this amounts to 900 to 1,300 calories a day, or about 225 to 325 grams.

Fiber is the part of plant-based foods that your body doesn't digest and absorb. There are two basic types of fiber: soluble and insoluble. Soluble fiber may help improve your cholesterol and blood sugar levels. Oats, dried beans and some fruits, such as apples and oranges, are good sources of soluble fiber. Insoluble fiber adds bulk to your stool and can help prevent constipation. Vegetables, wheat bran and other whole grains are good sources of insoluble fiber.

Recommendation: Emphasize whole-grain products, fruits, vegetables, beans and peas, and unsalted nuts and seeds. If you're a woman, get about 22 to 28 grams of fiber a day. If you're a man, get about 28 to 34 grams of fiber a day.

All sugar, whether natural or processed, is a type of carbohydrate that your body uses for energy. Sugar occurs naturally in some foods, including fruits, vegetables, milk and some grains. Sugar is also added to foods and beverages. These added sugars do little more than add calories to your diet. Many processed foods that have added sugar also contain solid fats.

Recommendation: Cut back on calories from added sugar and solid fats. For most people, that means cutting their intake to no more than 5 to 15 percent of total calories. (Consider that 13 percent of a 2,000-calorie diet is about 260 calories a day.) Limit table sugar, desserts, pizza, sausage and similar fatty meats, sweetened beverages, candy, stick margarine and butter.

The American Heart Association has specific guidelines for added sugar — no more than 100 calories a day from added sugar for most women and no more than 150 calories a day for most men. That's about 6 teaspoons for women and 9 for men.

Protein is an important nutrient, essential for growth and development. All the cells of your body include protein. Protein is also an important source of calories and energy. Both plant-based and animal-based foods provide protein.

Recommendation: Emphasize plant sources of protein, such as beans, lentils, soy products and unsalted nuts. These high-protein foods have the added bonus of being higher in health-enhancing nutrients than are animal sources of protein. Eat seafood twice a week. Meat, poultry and dairy products should be lean or low fat. Get 10 to 35 percent of your total daily calories from protein. Protein has 4 calories a gram. Based on a 2,000-calorie-a-day diet, this amounts to about 200 to 700 calories a day, or about 50 to 175 grams a day.

Fats aren't necessarily bad for you. Dietary fat is a nutrient that helps your body absorb essential vitamins, maintains the structure and function of cell membranes, and helps keep your immune system working. Some types of fat, though, may increase your risk of heart disease and other health problems. Fat also has a lot of calories, increasing the risk of weight gain.

Recommendation: Emphasize unsaturated fats from healthier sources, such as lean poultry, fish and healthy oils, such as olive, canola and nut oils. Limit less healthy full-fat dairy products, desserts, pizza, burgers, sausage and other fatty meats. To keep fat at bay, limit all sources of fat to 20 to 35 percent of your daily calories. Fat has 9 calories a gram. Based on a 2,000-calorie-a-day diet, this amounts to about 400 to 700 calories a day, or about 44 to 78 grams of total fat.

Saturated fat is most often found in animal products, such as cheese, red meat, poultry, butter and whole-milk products. Other foods high in saturated fat include those made with coconut, palm and other tropical oils. Saturated fat may increase your risk of heart disease and type 2 diabetes.

Recommendation: Replace saturated fats with healthier monounsaturated fats and polyunsaturated fats, found in olive oil, canola oil, vegetable oils, lean poultry, and unsalted nuts and seeds. Remember saturated fat counts toward your total daily allowance of fat. Limit saturated fat to no more than 10 percent of your total calories. Lowering calories from saturated fat to 7 percent can further reduce your risk of heart disease. Saturated fat has 9 calories a gram. Based on a 2,000-calorie-a-day diet, 7 to 10 percent amounts to about 140 to 200 calories a day, or about 16 to 22 grams of saturated fat.

Trans fat occurs naturally in some foods, especially foods from animals. But most trans fat is created during food processing through partial hydrogenation of unsaturated fats. Trans fat is found in some types of margarine, shortening, snack foods and commercial baked goods. Trans fat can increase your risk of heart disease.

Recommendation: Avoid trans fat as much as possible by limiting foods that contain synthetic sources of trans fat, such as partially hydrogenated oils, and by limiting other solid fats. Cut back on commercially prepared desserts and snacks, such as crackers, cookies, cakes and doughnuts. Remember trans fat counts toward your total daily allowance of fat.

Recommendation: Keep dietary cholesterol to less than 300 milligrams a day. Cutting cholesterol to less than 200 milligrams a day can benefit anyone at high risk of heart disease. Reduce dietary cholesterol by cutting back on animal sources of food, such as beef, poultry and egg yolks. If an item is high in saturated fat, it's probably also high in cholesterol.

Some sodium is vital because it helps maintain the right balance of fluids in your body, helps transmit nerve impulses, and influences the contraction and relaxation of muscles. Too much sodium, though, can be harmful, increasing your blood pressure and the risk of heart disease and stroke. Most Americans get far too much sodium in their daily diets and need to cut back.

Recommendation: Reduce sodium in your diet by limiting processed and prepared foods, which are often high in sodium. Also avoid salty condiments. Don't add salt at the table, and eliminate it from recipes when possible. Limit sodium to less than 2,300 milligrams a day — or 1,500 milligrams if you're age 51 or older, if you are black, or if you have high blood pressure, diabetes or chronic kidney disease.

Choosing the right foods helps promote health and reduces your risk of chronic diseases. It boils down to making meals that emphasize fresh, unprocessed plant-based foods, perhaps with a few lean animal products. This way of eating can also help you maintain calorie balance over time to achieve and sustain a healthy weight.

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